Methods and systems for synthesizing pickup images

Abstract

In an image pickup apparatus, a level compensator compensates the level of an image xL (i, j) sensed by an image sensor by exposure for a long time on the basis of the exposure of the image to produce a compensated image xL′ (i, j), while another level compensator compensates the level of an image xS (i, j) sensed by the image sensor by exposure for a short time on the basis of the exposure of the image to produce a compensated image xS′ (i, j). The image pickup apparatus also includes an image synthesizer to synthesize these compensates images xL′ (i, j) and xS′ (i, j) to produce a single synthetic image x (i, j). A dynamic range compressor also included in the image pickup apparatus compresses the synthetic image x (i, j) to produce a compressed image y (i, j) for delivery to outside.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This is a divisional application of U.S. patent application Ser. No. 09 / 468,053, filed Dec. 20, 1999, the entirety of which is incorporated herein by reference. This application claims the benefits of priority under 35 U.S.C. §119(a)-(d) to Japanese Patent Application No. 10-362899 filed on Dec. 21, 1998 in the Japanese Patent Office.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to an image pickup method and apparatus, adapted to synthesize a plurality of images having been acquired by picking up or sensing an object under different exposure conditions, respectively, to produce an image having an excellent gradation reproducibility, and more particularly, to an image pickup method and apparatus suitable for application to a video camera, still camera, monitor camera, on vehicle camera, etc. Also, the present invention relates to an image processing method and apparatus, adapted to receive a ...

AI Technical Summary

Benefits of technology

[0036]It is further object to overcome the above-mentioned drawbacks of the prior by providing an image processing method adapted to receive a plurality of images sensed in different exposure conditions, respectively, synthesize the input images and compress a synthetic image thus produced, to thereby produce a more natural image.

Problems solved by technology

On the other hand, in the image xS acquired by exposure for the short time, the saturation level is not reached even in the high-level region R1 but no sufficient contrast cannot be secured in the low-level region R2.

As having been described in the foregoing, the conventional image pickup methods including the aforementioned exposure control method, image synthesis method and image compression method are disadvantageous in that synthetic images and compressed images are not natural because a plurality of original images to be synthesized are acquired in different conditions, respectively.

The conventional image pickup methods are also disadvantageous in that since images acquired with larger exposure contain more flare spots, an image produced by synthesis of such sensed images has the level in the dark region thereof relatively increased as caused by the flare spots and thus a resultant image as a whole will be whitish.

Images